1. Field of the Invention
This invention relates to method and apparatus for cleaning elongated objects after they have been subjected to a surface treatment by a fluid medium.
2. Prior Art
The prior devices used for washing and drying surface treated objects of various materials in long lengths, such as strip, wire, rod and bars or fibres, show drawbacks which are unsatisfactory from technical and economic aspects.
Another disadvantage of prior devices is that technical difficulty and cost in complying with environmental regulations, particularly where contaminating washing agents are concerned, in which often the solvent is a constituent of the surface treating medium.
For achieving an acceptable surface cleanliness for an object, e.g. wire contaminated with acid or alkaline agents from a preceding surface treatment -- particularly as these agents have a considerable adherence to the surface of the material -- these prior devices are often provided for flushing as well as washing the object by immersion. This usage renders the devices more complicated in their structure and assembly and also requires more space, especially for high feeding speeds of the object, because several washing steps and stations must be used. The prior devices further have a comparatively high consumption of washing agent, a condition which increases the technical and economic investments for regenerating or otherwise treating the contaminated washing agent or agents for environmental protection.
Another factor that affects the content of impurities in the washing agent after its use, is the amount of medium carried by the wire to the washing station, said amount being difficult to control and varying when using the known devices. These conditions are caused by inefficient wiping devices with which these prior devices are provided for acting on the job before the washing. Usually, the wiping devices are felts, tow, or the like. Such methods and devices are unsatisfactory because after a short time of use, the wiping device becomes saturated by the wiped-off medium. The wear on these devices is considerable and causes the amount of medium adhering to the object to vary.
The flushing devices for prior devices require also regular care and maintenance, because the nozzles used will clog within a short period of time. Finally the drying by the prior devices is unsatisfactory. When drying an object after the washing, particularly at high object-feeding speeds moisture remaining on the surface may cause drawbacks, such as discoloration and/or corrosion.